Single-phase forming ability of high-entropy ceramics from a size disorder perspective: A case study of (La0.2Eu0.2Gd0.2Y0.2Yb0.2)2Zr2O7

• Published in: Ceramics international Vol. 48; no. 5; pp. 6956 - 6965
• Main Authors: Yang, Hongbo, Lin, Guangqiang, Bu, Huanpeng, Liu, Huijun, Yang, Lingxu, Wang, Wenjun, Lin, Xiaohuan, Fu, Chao, Wang, Yuansheng, Zeng, Chaoliu
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2022
• Subjects: High-entropy ceramics; Rare earth zirconates; Single-phase forming ability; Size disorder; Rare earth zirconates; Size disorder; High-entropy ceramics; Single-phase forming ability
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2021.11.252

A newly five-component equimolar high-entropy ceramic – (La0.2Eu0.2Gd0.2Y0.2Yb0.2)2Zr2O7 with a mixture phase of pyrochlore and fluorite structure was successfully synthesized. On this basis, a series of systematically designed and synthesized high or medium-entropy ceramics, accompanied by a large number of previous reports on multi-component rare earth zirconates, were summarized to jointly investigate the single-phase forming ability of high-entropy rare earth zirconates ceramics (HE-RE2Zr2O7 for short) in terms of entropy value and cationic radius difference (δ). Subsequently, the forming process and mechanism of dual-phase solid solution were analyzed. The conclusions indicated that the single-phase forming ability was more determined by the cationic radius difference rather than the entropy value，and the critical value of δ distinguishing single-phase between dual-phase zone was around 5.2%. In addition, the formation of dual-phase solid solution was essentially driven by the size disorder resulting from rattler effect of cations with significant difference in radius. This work is the first report on the single-phase forming ability of HE-RE2Zr2O7 and would pave new ways for predicting the formation of high-entropy phases.